Exit stdio-based analysis server when stdin closed.

pkg/analysis_server/test/channel_test.dart

Index: pkg/analysis_server/test/channel_test.dart
diff --git a/pkg/analysis_server/test/channel_test.dart b/pkg/analysis_server/test/channel_test.dart
index 2a11638014cb17125fb6e6537d95748bf07c504a..1f23745d5ae86bca23e5923599099acd40f7e28e 100644
--- a/pkg/analysis_server/test/channel_test.dart
+++ b/pkg/analysis_server/test/channel_test.dart
@@ -28,6 +28,7 @@ main() {
   });
   group('ByteStreamServerChannel', () {
     setUp(ByteStreamServerChannelTest.setUp);
+    test('closed', ByteStreamServerChannelTest.closed);
     test('listen_wellFormedRequest',
         ByteStreamServerChannelTest.listen_wellFormedRequest);
     test('listen_invalidRequest',
@@ -226,6 +227,11 @@ class ByteStreamServerChannelTest {
     });
   }
 
+  static Future closed() {
+    return inputSink.close().then((_) => channel.closed.timeout(new Duration(
+        seconds: 1)));
+  }
+
   static Future listen_wellFormedRequest() {
     inputSink.writeln('{"id":"0","method":"server.version"}');
     return inputSink.flush().then((_) => requestStream.first.timeout(